The present invention relates to apparatus for fusibly interconnecting pipes.
Metal pipes have long been used for distribution of town gas, but intermediate density polyethylene pipes are now widely used for the same purpose because they provide moderate rigidity and flexibility and because, due to their noncorrosive nature, they can be used semi-permanently.
Such polyethylene pipes are presently connected together by a fusion connection technique. This technique includes the steps of chamfering the fusible connecting surfaces, heating and fusing such surfaces with a heater, applying a specified pressure for a specified time period, and waiting for the pipes and the fused connection to cool. A variety of devices for performing this have been developed and proposed. However, these fusing connectors have various disadvantages. For example, a fusing connector proposed in Japanese patent application No. 40518/1981 is capable of holding a predetermined pressurizing force for a required period without any manpower. This and other fusing connectors all have a disadvantage that they require skill for correct operation. Namely, in the fusing connection processes, different times are often required for the steps of pressurizing and fusing, heating and holding, pressurized connecting, and cooling. The times also vary in accordance with the size of pipes being connected. An operator should remember such process times, but he may forget such data if he has not worked with the fusing connector for a while. Moreover, operators of existing fusing connectors must have and observe a timer or clock like a stopwatch in order to watch the processing time. At the conclusion of each phase of the process, the operator must reset the second hand to zero, restart the time, and continue to observe the time. In addition, there has been a problem when the next process step has been started due to confusion in the time observations for the respective processings.
An object of this invention is to provide an effective fusing connector for semi-automatically connecting thermoplastic resin pipes.